title: Extraordinary expansion of a Sorangium cellulosum genome from an alkaline milieu.
abstract: Complex environmental conditions can significantly affect bacterial genome size by unknown mechanisms. The So0157-2 strain of Sorangium cellulosum is an alkaline-adaptive epothilone producer that grows across a wide pH range. Here, we show that the genome of this strain is 14,782,125 base pairs, 1.75-megabases larger than the largest bacterial genome from S. cellulosum reported previously. The total 11,599 coding sequences (CDSs) include massive duplications and horizontally transferred genes, regulated by lots of protein kinases, sigma factors and related transcriptional regulation co-factors, providing the So0157-2 strain abundant resources and flexibility for ecological adaptation. The comparative transcriptomics approach, which detected 90.7% of the total CDSs, not only demonstrates complex expression patterns under varying environmental conditions but also suggests an alkaline-improved pathway of the insertion and duplication, which has been genetically testified, in this strain. These results provide insights into and a paradigm for how environmental conditions can affect bacterial genome expansion.
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan 250100, China.
authors.forename: Kui
authors.initials: K
authors.lastname: Han
authors.forename: Zhi-feng
authors.initials: ZF
authors.lastname: Li
authors.forename: Ran
authors.initials: R
authors.lastname: Peng
authors.forename: Li-ping
authors.initials: LP
authors.lastname: Zhu
authors.forename: Tao
authors.initials: T
authors.lastname: Zhou
authors.forename: Lu-guang
authors.initials: LG
authors.lastname: Wang
authors.forename: Shu-guang
authors.initials: SG
authors.lastname: Li
authors.forename: Xiao-bo
authors.initials: XB
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.forename: Zhi-hong
authors.initials: ZH
authors.lastname: Wu
authors.forename: Nan
authors.initials: N
authors.lastname: Qin
authors.forename: Yue-zhong
authors.initials: YZ
authors.lastname: Li
mesh_terms: D000468:Alkalies; D016680:Genome, Bacterial; D006863:Hydrogen-Ion Concentration; D009231:Myxococcales / Q000235:genetics*
chemical_list: D000468:Alkalies